1. Technical Field
The present invention relates to a liquid ejecting apparatus such as an ink jet type recording apparatus, and a method for controlling thereof, and in particular, to a liquid ejecting apparatus that performs a maintenance processing for recovering ejecting ability of a liquid ejecting head by ejecting liquid from a nozzle, and a method for controlling a liquid ejecting apparatus.
2. Related Art
A liquid ejecting apparatus is an apparatus that includes a liquid ejecting head, and ejects (discharges) various kinds of liquid from the liquid ejecting head. For example, as the liquid ejecting apparatus, there is an image recording apparatus such as an ink jet type printer and an ink jet type plotter, but recently, the liquid ejecting apparatus is also applied to various kinds of manufacturing apparatuses by making use of a feature which is capable of precisely landing a very small amount of the liquid in a predetermined position. For example, the liquid ejecting apparatus is applied to a display manufacturing apparatus that manufactures a color filters of a liquid crystal display or the like, an electrode forming apparatus that forms an electrode of an organic electro luminescence (EL) display, a field emission display (FED) or the like, and a chip manufacturing apparatus that manufactures a biochip (biological chemistry element). Therefore, in a recording head for the image recording apparatus, ink is ejected in a liquid shape, and in a color material ejecting head for the display manufacturing apparatus, a solution of each color material of R (Red), G (Green), and B (Blue), is ejected. Moreover, in an electrode material ejecting head for the electrode forming apparatus, an electrode material is ejected in a liquid shape, and in a bio-organic matter ejecting head for the chip manufacturing apparatus, a solution of the bio-organic matter is ejected.
Here, in the liquid ejecting apparatus described above, the liquid within the head is thickened by evaporating a solvent through a surface (meniscus) of the ink which is exposed at the nozzle of the liquid ejecting head. Accordingly, there are circumstances where a ejecting failure of not ejecting the liquid from the nozzle, or wherein a flight direction of the liquid which is ejected from the nozzle is bent. Hence, in the liquid ejecting apparatus of the kind described above, in order to suppress the ejecting failure, maintenance processing is performed for forcibly ejecting the liquid from the nozzle which is referred to as flushing, is performed, which is distinct from an ejecting processing of the liquid with respect to a landing target such as a recording medium or the like. Specifically, for example, whenever a fixed time is elapsed or whenever a pass (scan unit of the liquid ejecting head) is performed a predetermined times in the ejecting processing, a recording head is transferred up to an ink receiving member which is in the position out of the recording medium, so that droplets are repeatedly ejected from a nozzle into the position thereof (for example, JP-A-2004-066677).
In the flushing described above, a drive waveform (drive pulse) (which is used in a liquid ejecting processing with respect to the landing target such as the recording medium or the like), or a drive waveform only for the flushing, is used. Therefore, a pressure generation unit is driven by applying the drive waveform to the pressure generation unit, and thereby, a pressure variation is generated to the liquid within a pressure chamber to communicate with the nozzle. Accordingly, the liquid is ejected (made to be shot) from the nozzle using the pressure variation. At this time, in general, after the meniscus within the nozzle is pulled into the pressure chamber side once by firstly decompressing the inside of the pressure chamber, the meniscus is pushed out onto an opposite side (ejecting side) to the pressure chamber side by rapidly pressurizing the inside of the pressure chamber, and the droplets are ejected from the nozzle. By continuously repeating such operations the predetermined times, the liquid which is thickened within the nozzle and the pressure chamber, is discharged.
Moreover, the case of performing the flushing by a so-called push shooting manner, is proposed (for example, see JP-A-09-150506). That is, by pressurizing the inside of the pressure chamber without first performing the decompression of the pressure chamber, the meniscus within the nozzle is pushed out onto the opposite side (ejecting side) to the pressure chamber side from an initial position, and the droplets are ejected from the nozzle.
In a configuration of ejecting the liquid by using a reaction after pulling the meniscus into the pressure chamber side in the flushing as described in JP-A-2004-066677, it is possible to eject a lot of liquid at one time, and to efficiently discharge the thickened liquid in the vicinity of the nozzle. On the other hand, when degrees of thickening are relatively slight, there is a problem of wasting the liquid by consuming the liquid more than necessary. Additionally, when the inside of the pressure chamber is decompressed in order to pull the meniscus into the pressure chamber side, the thickened liquid in the vicinity of the nozzle is diffused to the pressure chamber side, and there is the problem of generating the necessity to discharge rather more liquid in order to discharge the thickened liquid which is diffused. On the other hand, in the configuration of ejecting the droplets from the nozzle by the so-called push shooting manner as described in JP-A-09-150506, since force for stirring the liquid is weak in comparison with the former configuration, when the thickening of the liquid relatively proceeds, there is a problem of being difficult to eject the liquid without being capable of diffusing the thickened liquid in the vicinity of the nozzle. Hereby, in order to discharge the thickened liquid, the flushing ought to be performed more times, and as a result, it is likely to consume a lot of liquid.